Small children outgrow shoes very quickly and often do not realize that they are wearing shoes that are too tight. Although parents try to assess the situation, the child does not always cooperate; the parents sometimes overcompensate by buying new shoes thinking the old ones are too tight when the fit is still good. It would be desirable to have shoes that would objectively indicate the condition of being too tight.
For amusement and/or safety purposes, some children's shoes are equipped with lights that flash on and off as they walk or run. U.S. Pat. No. 5,408,764 of Wut discloses a motion activated light module fitted in the heel of such shoes. While the light emitting diodes (LED's) used could be used for indicating that the shoes are too tight, they are not used for this purpose by Wut '764. U.S. Pat. No. 5,033,291 of Podoloff et al. discloses a flexible tactile sensor for measuring foot bottom pressure. Using pressure-sensitive resistive material between two orthogonal layers of electrodes, the resistance at each electrode intersection can be used to infer the pressure of the bottom of the foot against the support layer of a shoe or orthotic appliance. External electronics is then used to map the foot bottom pressure; this, in turn, can be used to modify or improve orthotics or special shoes for people with problem feet. This technology is too sophisticated for the current application since the only information required is that a tightness threshold has been exceeded.